package com.qsmx.store.app.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

/**
 * @preserve all
 * @author Administrator
 * 
 */
public class Base64
{
	private static char[] base64EncodeChars = new char[] { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
			'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4',
			'5', '6', '7', '8', '9', '+', '/' };

	private static byte[] base64DecodeChars = new byte[] { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
			-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8,
			9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,
			45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };

	private Base64()
	{
	}

	public static String encode(byte[] data)
	{
		if (null == data)
		{
			return "";
		}
		StringBuffer sb = new StringBuffer();
		int len = data.length;
		int i = 0;
		int b1, b2, b3;

		while (i < len)
		{
			b1 = data[i++] & 0xff;
			if (i == len)
			{
				sb.append(base64EncodeChars[b1 >>> 2]);
				sb.append(base64EncodeChars[(b1 & 0x3) << 4]);
				sb.append("==");
				break;
			}
			b2 = data[i++] & 0xff;
			if (i == len)
			{
				sb.append(base64EncodeChars[b1 >>> 2]);
				sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
				sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);
				sb.append("=");
				break;
			}
			b3 = data[i++] & 0xff;
			sb.append(base64EncodeChars[b1 >>> 2]);
			sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
			sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);
			sb.append(base64EncodeChars[b3 & 0x3f]);
		}
		return sb.toString();
	}

	public static byte[] decode(String str)
	{
		byte[] data = str.getBytes();
		byte[] result = null;
		int len = data.length;
		ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
		int i = 0;
		int b1, b2, b3, b4;

		try
		{
			while (i < len)
			{

				/* b1 */
				do
				{
					b1 = base64DecodeChars[data[i++]];
				} while (i < len && b1 == -1);
				if (b1 == -1)
				{
					break;
				}

				/* b2 */
				do
				{
					b2 = base64DecodeChars[data[i++]];
				} while (i < len && b2 == -1);
				if (b2 == -1)
				{
					break;
				}
				buf.write((b1 << 2) | ((b2 & 0x30) >>> 4));

				/* b3 */
				do
				{
					b3 = data[i++];
					if (b3 == 61)
					{
						return buf.toByteArray();
					}
					b3 = base64DecodeChars[b3];
				} while (i < len && b3 == -1);
				if (b3 == -1)
				{
					break;
				}
				buf.write(((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2));

				/* b4 */
				do
				{
					b4 = data[i++];
					if (b4 == 61)
					{
						return buf.toByteArray();
					}
					b4 = base64DecodeChars[b4];
				} while (i < len && b4 == -1);
				if (b4 == -1)
				{
					break;
				}
				buf.write(((b3 & 0x03) << 6) | b4);
			}
			result = buf.toByteArray();
		} catch (Exception e)
		{
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally
		{
			try
			{
				buf.close();
			} catch (IOException e)
			{
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return result;
	}
}
